CN114041074A

CN114041074A - Optical device comprising a wavelength-selective optical filter with a down-converter

Info

Publication number: CN114041074A
Application number: CN202080048724.7A
Authority: CN
Inventors: 约翰·A·惠特利; 马克·A·勒里希
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2019-07-02
Filing date: 2020-06-23
Publication date: 2022-02-11
Anticipated expiration: 2040-06-23
Also published as: WO2021001726A1; US20220357205A1; EP3994611A1; US11879779B2; CN114041074B

Abstract

The invention discloses an optical system (150) comprising: an optical sensor (154); a plurality of light-sensitive pixels (178) disposed on the optical sensor; a wavelength-selective optical filter (158) in optical communication with the light-sensitive pixels, the wavelength-selective optical filter being disposed remotely from the optical sensor; and a plurality of spatially varying regions (220,224,228,232) disposed in the optical filter, at least one of the plurality of spatially varying regions comprising a down-converter (400, 500).

Description

Optical device comprising a wavelength-selective optical filter with a down-converter

Background

Optical filters are used in a variety of applications including optical communication systems, optical sensors, imaging, scientific optical devices, and display systems. Such optical filters may include optical layers that manage the transmission of incident electromagnetic radiation (including light).

Optical filters may reflect or absorb some portions of incident light and transmit or convert other portions of incident light. The layers within an optical filter may also differ in wavelength selectivity, optical transmission, optical clarity, optical haze, and refractive index. Systems involving optical sensors and optical filters may collect specific electromagnetic data based on the properties of the optical filter.

Disclosure of Invention

In some aspects, the present disclosure provides an optical system. The optical system may include: an optical sensor; a plurality of photosensitive pixels disposed on the optical sensor; and a wavelength selective optical filter in optical communication with the light-sensitive pixels. The wavelength-selective optical filter may be disposed remotely from the optical sensor, and a plurality of spatially varying regions may be disposed in the optical filter. At least one of the plurality of spatially varying regions may comprise a down-converter.

In some aspects, the present disclosure provides an optical device. The optical device may include: an optical sensor; a plurality of photosensitive pixels disposed on the optical sensor; and a wavelength selective optical filter in optical communication with the light-sensitive pixels. A first plurality of spatially varying regions may be disposed in the optical filter, at least one of the first plurality of spatially varying regions may comprise a down-converter. A second plurality of spatially varying regions, the second plurality of spatially varying regions being disposable in the optical filter;

in some aspects, the present disclosure provides an optical device. The optical means may comprise a wavelength selective optical filter. The optical filter may include a first plurality of spatially varying regions disposed in the optical filter, at least one region of the first plurality of spatially varying regions may include a down-converter, and a second plurality of spatially varying regions may be included in the optical filter.

Drawings

Fig. 1 is a schematic perspective view of a reflective film according to an exemplary embodiment of the present disclosure.

Fig. 2A to 2K are schematic diagrams of an optical system according to an exemplary embodiment of the present disclosure.

Fig. 3 is a front elevation view of an optical sensor and included pixels according to an exemplary embodiment of the present disclosure.

Fig. 4A is a front elevation view of a first filter sheet, fig. 4B is a front elevation view of a second filter sheet, and fig. 4C is a front elevation view of another embodiment of the first filter sheet according to an exemplary embodiment of the present disclosure.

Fig. 5A is a front elevation view of a first filter sheet and a second filter sheet adjacent to each other and forming an optical filter, fig. 5B is a top elevation view of a first filter sheet and a second filter sheet adjacent to each other and forming an optical filter, and fig. 5C is a side elevation view of a first filter sheet and a second filter sheet adjacent to each other and forming an optical filter according to an exemplary embodiment of the present disclosure.

Fig. 6 is a front elevation view of an exemplary first or second filter sheet including various area shapes according to an exemplary embodiment of the present disclosure.

Fig. 7 shows a schematic view of an optical filter and an optical sensor according to an exemplary embodiment of the present disclosure.

Fig. 8 illustrates an optical filter proximate an optical sensor further illustrating the relative positions of regions, areas, and pixels according to an exemplary embodiment of the present disclosure.

Fig. 9A to 9F are schematic views of an optical device according to an exemplary embodiment of the present disclosure.

Fig. 10 is a view of an optical filter including a down-converter according to an exemplary embodiment of the present disclosure.

Fig. 11 is a view of an optical filter according to an exemplary embodiment of the present disclosure, which is different from the optical filter shown in fig. 10.

Fig. 12 illustrates a spatially varying optical filter according to an exemplary embodiment of the present disclosure.

Fig. 13 illustrates another spatially varying optical filter according to an exemplary embodiment of the present disclosure.

Detailed Description

In the following description, reference is made to the accompanying drawings, which form a part hereof and in which is shown by way of illustration various embodiments. The figures are not necessarily to scale. It is to be understood that other embodiments and implementations are contemplated and may be made without departing from the scope or spirit of the present description. The following detailed description is, therefore, not to be taken in a limiting sense.

Multilayer optical films, i.e., films that provide desired transmission and/or reflection characteristics at least in part by the arrangement of microlayers having different refractive indices, are known. Multilayer optical films have also been shown by coextrusion of alternating polymer layers. See, e.g., U.S. Pat. Nos. 3,610,729(Rogers), 4,446,305(Rogers et al), 4,540,623(Im et al), 5,448,404(Schrenk et al), and 5,882,774(Jonza et al). In such polymeric multilayer optical films, the polymeric materials are used primarily or exclusively in the preparation of the various layers. These polymeric multilayer optical films may be referred to as thermoplastic multilayer optical films. Such films are suitable for high-volume manufacturing processes and can be made into large sheets and rolls.

Multilayer optical films include individual microlayers having different refractive index characteristics such that some light is reflected at interfaces between adjacent microlayers. The microlayers are sufficiently thin such that light reflected at the plurality of interfaces undergoes constructive or destructive interference in order to impart desired reflective or transmissive properties to the multilayer optical film. For multilayer optical films designed to reflect ultraviolet, visible, or near-infrared wavelengths of light, each microlayer may have an optical thickness (physical thickness multiplied by refractive index) of less than about 1 μm. The layers can generally be arranged to be thinnest to thickest. In some embodiments, the arrangement of alternating optical layers may vary substantially linearly according to the layer count. These layer profiles may be referred to as linear layer profiles. Thicker layers may also be included, such as skin layers at the outer surface of the multilayer optical film or Protective Boundary Layers (PBLs) disposed within the multilayer optical film to separate coherent groups of microlayers (referred to herein as "packets"). In some cases, the protective boundary layer can be the same material as the alternating layers of the at least one multilayer optical film. In other cases, the protective boundary layer may be a different material selected for its physical or rheological properties. The protective boundary layer may be on one or both sides of the optical packet. In the case of a single-packet multilayer optical film, the protective boundary layer can be on one or both outer surfaces of the multilayer optical film.

As will be discussed below, the present disclosure provides an optical system for analyzing the spectrum of one or more regions. With various components and techniques, the optical system can be optimized to collect measured optical data having a particular absorption spectrum. Non-limiting applications may include multispectral "liveness" detection of fingerprints or other biometrics, healthcare diagnostics including telemedicine modalities, component authentication using spectra as an identifying feature, and many other possible uses.

Fig. 1 is a schematic perspective view of a reflective film. Fig. 1 shows a light ray 130 incident on the reflective film 110 at an incident angle θ, thereby forming an incident plane 132. The reflective film 110 includes a first reflective axis 116 parallel to the x-axis and a second reflective axis 114 parallel to the y-axis. The plane of incidence 132 of the light ray 130 is parallel to the first axis of reflection 116. The light ray 130 has a p-polarized component lying in a plane of incidence 132 and an s-polarized component orthogonal to the plane of incidence 132. The p-polarized light of ray 130 will be provided with R_pp-xThe reflective film of reflectivity reflects (projection of the electric field of the p-polarized light of ray 130 onto the plane of reflective film 110 is parallel to the x-direction) while the s-polarized light of ray 130 is reflected with R_ss-yReflective film reflection of reflectivity (electric field of s-polarized light of ray 130 parallel to y-direction)。

Further, fig. 1 shows a light ray 120 incident on the reflective film in an incident plane 122 parallel to the second reflective axis 114 of the film 110. The light ray 120 has a p-polarized component lying in a plane of incidence 122 and an s-polarized component orthogonal to the plane of incidence 122. The p-polarized light of ray 120 will be provided with R_pp-yThe reflective film of reflectivity reflects while the s-polarized light of ray 120 is reflected with R_ss-xThe reflective film of the reflectivity reflects. The amount of transmission and reflection of p-polarized light and s-polarized light for any plane of incidence will depend on the properties of the reflective film.

Fig. 2A schematically illustrates an exemplary optical system 150. In some embodiments, the optical system 150 includes an optical sensor 154, an optical filter 158, a light source 162, and a reflector 163. A measurement object 170 is also shown. In some embodiments, light emitted from the light source 162 passes through the optical filter 158 and the measurement object 170, reflects from the reflector 163, and then passes back through the measurement object 170 and the optical filter 158 before reaching the optical sensor 154. Optical path 173A can be seen starting from light source 162, reflecting from reflector 163, and then reaching optical sensor 154.

Fig. 2B schematically illustrates an exemplary optical system 150. In some embodiments, the optical system 150 includes an optical sensor 154, an optical filter 158, a light source 162, and a reflector 163. A measurement object 170 is also shown. In some embodiments, light emitted from the light source 162 passes through the measurement object 170 and the optical filter 158, reflects from the reflector 163, and then passes back through the optical filter 158 and the measurement object 170 before reaching the optical sensor 154. Optical path 173B can be seen starting from light source 162, reflecting from reflector 163, and then reaching optical sensor 154.

Fig. 2C schematically illustrates an exemplary optical system 150 similar to the exemplary optical system illustrated in fig. 2A. However, the optical sensor 154 and the light source 162 may be included in the remote optical device 160. The remote optical device 160 may be a mobile phone, a tablet computer, a computer, or any other medical, electrical, or electromechanical device. Optical path 173C can be seen traveling from light source 162 to the reflector and then to optical sensor 154.

Fig. 2D schematically illustrates an exemplary optical system 150 similar to that of fig. 2B. However, the optical sensor 154 and the light source 162 may be included in the remote optical device 160. Optical path 173D can be seen traveling from light source 162 to reflector 163 and then to optical sensor 154.

Fig. 2E schematically illustrates an exemplary optical system 150. In some embodiments, ambient light and/or light emitted from the measurement object 170 passes through the optical filter 158 before reaching the optical sensor 154. The optical path 173E can be seen to be located between the measurement object 170 and the optical sensor 154.

Fig. 2F schematically illustrates an exemplary optical system 150. In some embodiments, ambient light passes through the optical filter 158 before reaching the optical sensor 154. The optical path 173F can be seen to be located between the optical filter 158 and the optical sensor 154.

Fig. 2G schematically illustrates an exemplary optical system 150. In some embodiments, light emitted from the light source 162 and/or ambient light passes through the measurement object 170 and the optical filter 158 before reaching the optical sensor 154. Optical path 173G can be seen between light source 162 and optical sensor 154.

Fig. 2H schematically illustrates an exemplary optical system 150. In some embodiments, light emitted from the light source 162 and/or ambient light passes through the optical filter 158 and the measurement object 170 before reaching the optical sensor 154. Optical path 173H can be seen to be located between light source 162 and optical sensor 154.

Fig. 2I schematically illustrates an exemplary optical system 150. In some embodiments, the optical system 150 includes an angle-selective filter 166. Light emitted from the light source 162 passes through elements of the optical system 150, reflects from the reflector 163, and then passes through the measurement object 170, the optical filter 158, and the angle-selective filter 166 before reaching the optical sensor 154. Optical path 173I can be seen starting from light source 162, reflecting from reflector 163, and then reaching optical sensor 154.

Fig. 2J schematically illustrates an exemplary optical system 150 similar to the exemplary optical system illustrated in fig. 2I. In some embodiments, optical system 150 includes a second angularly selective filter 167 disposed along optical path 173J, as will be described below.

Fig. 2K schematically shows an exemplary optical system comprising crossed polarizer 171. In some embodiments, light source 162 is a polarized light source, whereby at least some light emitted from the polarized light source is reflected from reflector 163 along optical path 173K such that only light reflected by reflector 163, or substantially only light reflected by the reflector, is detected by optical sensor 154 due to the polarizing properties of the light and the corresponding pass characteristics of crossed polarizer 171.

In some embodiments, the reflector 163 reflects all, substantially all, or a portion of the light incident on the reflector 163. In some implementations, the reflector 163 can be a specular, semi-specular, lambertian, diffuse, or retroreflector. Where the reflector 163 is a retroreflector, the retroreflector 163 may be one of a cube corner reflector (such as 3M Diamond Grade sheeting) or a bead-based retroreflector (such as 3M Scotchlite) or a phase conjugate retroreflector.

In certain exemplary embodiments of the present disclosure, the term "remote" may mean disposed a distance from … …, disposed a minimum distance from … …, disposed at least 1 millimeter, 5 millimeters, 10 millimeters, 20 millimeters, 30 millimeters, 40 millimeters, 50 millimeters, 60 millimeters, 70 millimeters, 80 millimeters, 90 millimeters, 100 millimeters, 150 millimeters, 200 millimeters, 250 millimeters, 500 millimeters, 1000 millimeters, 2,000 millimeters, or 10,000 millimeters from … …, at least 1 kilometer from … …, separated from … …, not in contact with … …, not adjacent to … …, and/or not integrated with … …. As can be seen in fig. 2A to 2K, the optical sensor 154 may be disposed remotely from the measurement object 170, the optical filter 158, the reflector 163, the light source 162, the angle-selective filter 166, the second angle-selective filter 167, and/or the cross-polarizer 171. The light source 162 may be located remotely from the measurement object 170, the optical filter 158, the reflector 163, the light source 162, the angle-selective filter 166, the second angle-selective filter 167, the optical sensor 154, and/or the cross-polarizer 171. The remote optical device 160 may be located remotely from the measurement object 170, the optical filter 158, the reflector 163, the light source 162, the angle-selective filter 166, the second angle-selective filter 167, and/or the cross-polarizer 171. It should be understood that the measurement object 170 may be disposed anywhere along any disclosed optical path, and further, the measurement object 170 may be a liquid, a solid, or a gas.

In some implementations, the light source 162 can include one or more of: organic light emitting diodes, inorganic light emitting diodes, mini light emitting diodes, micro light emitting diodes, incandescent filaments, light emitting diodes, vertical cavity surface emitting lasers, or the optical sensor 154 itself may emit light. In some embodiments, an array of one or more of these types of light sources may form light source 162.

It should be understood that the aforementioned elements of optical system 150 may be disposed in any arrangement, order, or arrangement, that may contact, not contact, be adjacent, be proximate or be joined while still being in optical communication, and still fall within the scope of the disclosed optical system 150. Fig. 2A-2K illustrate only exemplary embodiments of optical system 150. For example, any of the exemplary optical systems 150 shown in fig. 2A-2K may include a crossed polarizer 171. In addition, any of the exemplary optical systems 150 shown in fig. 2A-2K may include an angle-selective filter 166, or an angle-selective filter 166 and a second angle-selective filter 167.

The optical sensor 154 may sense light over a single area or may be divided into a plurality of spotlight sensing picture elements or pixels 178. These pixels 178 can be seen in exemplary FIG. 3. One or more of the pixels 178 may serve as reference pixels 182, as will be described in more detail below. The optical sensor 154 may comprise a charge coupled device, a complementary metal oxide semiconductor, or may employ any other photosensitive sensor technology or combination of photosensor technologies. Additionally, the optical sensor 154 may include one or more photosensors, organic photosensors, photodiodes, and/or organic photodiodes.

In some embodiments, the optical sensor 154 and/or the optical filter 158 are flexible. Such flexible optical sensors 154 or optical filters 158 may have the characteristic of being bendable without cracking. Such flexible optical sensors 154 or optical filters 158 may also be capable of being formed into a roll. In some embodiments, the flexible optical sensor 154 or optical filter 158 may be bent around a core having a radius of curvature of, or at most: 7.6 centimeters (cm) (3 inches), 6.4cm (2.5 inches), 5cm (2 inches), 3.8cm (1.5 inches), 2.5cm (1 inch), 1.9cm (3/4 inches), 1.3cm (1/2 inches), or 0.635cm (1/4 inches).

Fig. 4A shows an exemplary first filter 190, and fig. 4B shows an exemplary second filter 194. The optical filter 158 may include a first filter 190 and/or a second filter 194. First filter 190 and second filter 194 may be formed from one or more optical film groupings, as described above. One or more writing regions 198 may be defined or formed in first filter 190. Writing area 198 may be a physical hole formed in first filter 190 by other processes such as die cutting, laser ablation, heating, spatially varying coating, printing, ink jet printing, laser printing, and/or water jet cutting.

Further, as shown in fig. 4C, an exemplary embodiment of first filter 190 includes a writing area 198 and one or more auxiliary writing areas 199. The writing area 198 and the auxiliary writing area 199 may have different sizes, shapes, and/or spatial patterns on the first filter 190. One or more of the auxiliary writing areas 199 may be larger than one or each of the pixels 178. Further, one or more of the auxiliary writing regions 199 generate or define an auxiliary transmission spectrum, which may be the same as or different from the transmission spectrum defined or generated by writing region 198. It should be understood that the

write zones

198, 204 may be formed in the same manner as the auxiliary write zone 199.

In some implementations, the

write zones

198, 204 and the auxiliary write zone 199 include a down-converter or down-conversion material, as will be described in more detail below.

Writing region 198 may also be formed using spatially tailored optical film processes, such as those described in U.S. patent 9,810,930(Merrill et al), which is incorporated herein by reference. In particular, the laser process can locally break birefringence, thereby changing the optical properties and transmission spectrum of a writing region (such as writing region 198). These written regions may be made completely transparent, or may have a wavelength selective function (or transmission spectrum) different from that of the non-written regions 200 of the first filter 190. One or more writing regions 204 may be defined or formed in second filter sheet 194 by any of the previously described ways of forming writing regions 198 in first filter sheet 190. Further, a non-written area 206 of the second filter 194 is shown in fig. 4B. Thus, the optical filter 158 may be a spatially varying optical filter, a wavelength-selective optical filter, or a spatially varying wavelength-selective optical filter, as will be described in further detail. Writing region 198 may have a different shape and/or size within first filter 190 and writing region 204 may have a different shape and/or size within second filter 194.

Write zones 198 may be arranged in a pattern or repeating pattern such that write zones 198 are set in a predictable manner. Similarly, the writing zones 204 may be arranged in a pattern or repeating pattern such that the writing zones 204 are disposed in a predictable manner. When first filter 190 and second filter 194 are adjacent, in contact, near, or joined to each other, the patterns of writing

regions

198 and 204 may be the same, similar, distinct, overlapping, corresponding, partially overlapping, or unrelated. In other words, when first filter 190 and second filter 194 are adjacent, in contact, near, or joined to each other in a particular manner, writing regions 198 and writing regions 204 may overlap, correspond, partially overlap, be unrelated, identical, similar, or dissimilar.

An embodiment of an optical filter 158 is shown in fig. 5A. In some embodiments, the optical filter 158 includes a first filter 190 and a second filter 194, and further the first filter 190 and the second filter 194 may be in contact with, adjacent to, or in close proximity to each other. In some embodiments, first filter sheet 190 and second filter sheet 194 are joined or laminated together by one of a variety of known joining techniques (including welding, adhesives, and lamination, among others).

In some embodiments, as shown in fig. 5A, 5B, and 5C, the writing

regions

198 and 204 partially overlap when the first filter sheet 190 and the second filter sheet 194 are adjacent, in contact, near, or joined to each other in a particular manner to form the optical filter 158. In such an arrangement, light rays incident on the front surface 209 of the optical filter 158 or incident on the entire front surface 209 of the optical filter 158 pass through each of four different regions: a first region 220 in which incident light passes through the non-writing region 200 of the first filter 190 and the non-writing region 206 of the second filter 194; a second region 224 in which incident light passes through the writing region 198 in the first filter 190 and through the writing region 204 in the second filter 194; a third region 228 in which incident light passes through the non-writing region 200 of the first filter 190 and passes through the writing region 204 in the second filter 194; and a fourth region 232 in which incident light passes through the non-writing region 206 of the second filter 194 and passes through the writing region 198 of the first filter 190. With this exemplary embodiment of the optical filter 158, light rays of incident light may pass through each of the regions 220,224,228, and 232 to be filtered in four different ways by varying the influence of the first filter 190 and the second filter 194.

In some embodiments, writing

regions

198, 204 and/or regions 220,224,228, and 232 may have various shapes having the same transmission spectrum. In particular, one of writing

regions

198, 204 and/or regions 220,224,228, and 232 may have a first shape and a first transmission spectrum, while another of writing

regions

198, 204 and/or regions 220,224,228, and 232 may have a second shape different from the first shape and a second transmission spectrum different from the first transmission spectrum.

In some embodiments, regions 220,224,228, and 232 may be independent of writing

zones

198, 204, and instead may simply represent geometric regions in one or more of first filter 190, second filter 194, and optical filter 158, such as those exemplarily illustrated by regions 220,224,228, and 232 in fig. 4A-8.

In some embodiments, writing

zones

198, 204 and/or regions 220,224,228, and 232 may include various absorbing materials, such as dyes and/or pigments. The absorbing material may be adhered to, inserted into, or formed within first, second, and/or

third filter sheets

190, 158, and/or 194, and may be printed, printed using an elastomeric printing or offset technique, coated, or extruded onto first, second, and/or 158

filter sheets

190, 194.

In some embodiments, the first and

second filter sheets

190 and 194 may be adhered together using an adhesive to form the optical filter 158, and the adhesive may include an absorbing material.

In some embodiments, a first absorbent material may be adhered to, inserted into, coated onto, or formed within first filter sheet and may form writing region 198, while a second absorbent material may be adhered to, inserted into, or formed within second filter sheet 194 and may form writing region 204. The first absorbing material may have a transmission spectrum different from the transmission spectrum of the second absorbing material. In some embodiments, the first absorbing material absorbs light having a wavelength of about 400nm to 700nm, and the second absorbing material absorbs light having a wavelength of about 400nm to 1000 nm. In view of the different blocking and passing properties of the first and second absorbing materials, as well as the exemplary configuration of the first and

second filters

190, 194 used to form the optical filter 158 as shown in fig. 5A, light along the optical path may thus be filtered to provide valuable data about the measurement object 170 when absorbed by the optical sensor 154.

In some embodiments of the optical filter 158, one or more absorptive filters formed of absorptive material may be patterned on the reflective interference filter.

In some embodiments, writing region 198 disposed in first filter 190 and/or writing region 204 disposed in second filter 194 may include a particular shape. For example, at least some of the writing regions 198 disposed in the first filter 190 and/or at least some of the writing regions 204 disposed in the second filter 194 may include one or more of: circular, square, triangular, elliptical, rectangular, pentagonal, hexagonal, heptagonal, octagonal, organic, partially organic, parallelogram, polygonal, and non-polygonal organic shapes. Examples of these shapes are shown in non-limiting manner in fig. 6. It should be appreciated that one or more of the writing regions 198 in the first filter 190 and the writing regions 204 in the second filter 194 may form one or more of these shapes in any order, arrangement, or permutation. Further, one or more of the writing regions 198 in the first filter 190 and the writing regions 204 in the second filter 194 may be the same shape or may be different shapes.

In some embodiments, the writing region 198 in the first filter 190 and/or the writing region 204 in the second filter 194 may comprise a particular size. Further, one or more of the writing regions 198 in the first filter 190 and the writing regions 204 in the second filter 194 may be the same size or may be different sizes. The respective sizes of the writing areas may vary depending on the sensing application, but may be selected to be larger than the size of the pixels 178 used in the optical sensor 154, such that a plurality of pixels 178 are used to collect light to increase the detection power of the spectral region defined by the writing areas. The optical sensor pixels 178 can then be grouped by hardware or software methods to align those pixels 178 with the writing area, resulting in a spectral-spatial mapping of the measurement layer or measurement object. In certain implementations, any one or more of the

write zones

198, 204, the auxiliary write zone 199, and/or the areas 220,224,228,232 may be greater than one pixel 178, greater than two pixels 178, greater than five pixels 178, greater than ten pixels 178, greater than one hundred pixels 178, greater than one thousand pixels 178, or greater than any number of pixels 178.

As shown in fig. 7, the optical filter 158 may be in optical communication with the optical sensor 154. In other words, light incident on the optical filter 158 may pass through one or more regions (220,224,228,232) of the optical filter 158 and then reach the optical sensor 154. The optical filter 158 may be adjacent to, in contact with, coupled to, near, or distal to the optical sensor 154 while still being in optical communication with the optical sensor 154. Fig. 7 shows the optical filter 158 and the optical sensor 154, thereby bringing the optical sensor close to or adjacent to the optical sensor 154. Fig. 8 illustrates a possible relationship between the optical filter 158 and the optical sensor 154, where the optical sensor 154 is adjacent to, or in contact with the optical filter 158.

As can be seen in fig. 7 and 8, in some embodiments, at least some of the pixels 178 are smaller than the writing region 198 in the first filter 190, the writing region 204 in the second filter 194, the first region 220, the second region 224, the third region 228, and/or the fourth region 232. Further, in some embodiments, each of the pixels 178 is smaller than the writing region 198 in the first filter 190, the writing region 204 in the second filter 194, the first region 220, the second region 224, the third region 228, and/or the fourth region 232. Depending on the composition of the optical filter 158, the at least one pixel 178 may be in optical communication with one of the writing region 198, the writing region 204, the first region 220, the second region 224, the third region 228, and the fourth region 232, such that light incident on the optical system 150 and affected by the aforementioned portion of the optical filter 158 is registered to and recorded by the at least one pixel 178. Additionally, as previously described, the presence of other elements (such as the light source 162 or the angle-selective filter 166) does not preclude the optical filter 158 from being in optical communication with the optical sensor 154, even if the optical filter 158 is not adjacent to, in contact with, or in close proximity to the optical sensor 154.

Each portion of the first filter 190, the second filter 194, and the optical filter 158 defines or produces one or more transmission spectra. It should be understood that such one or more transmission spectra define a wavelength range of light that is transmitted, substantially transmitted, 90% transmitted, substantially 90% transmitted, or partially transmitted. Similarly, light having wavelengths outside of one or more transmission spectra is blocked, substantially blocked, or partially blocked. In some embodiments, the visible spectrum is defined as 400nm to 700nm, or about 400nm to 700nm, the near infrared spectrum is defined as 700nm to 2000nm, or about 700nm to 2000nm, and the near ultraviolet spectrum is defined as 350nm to 400nm, or about 350nm to 400 nm.

In some embodiments, the transmission spectrum of non-writing region 200 of first filter 190 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum. In some embodiments, the transmission spectrum of the non-writing region 206 of the second filter 194 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum.

In some embodiments, the transmission spectrum of the writing region 198 of the first filter 190 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum. In some embodiments, the transmission spectrum of the auxiliary writing region 199 of the first filter 190 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum. In some embodiments, the transmission spectrum of the writing region 204 of the second filter 194 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum.

In some embodiments, the transmission spectrum of the first region 220 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum. In some embodiments, the transmission spectrum of second region 224 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum. In some embodiments, the transmission spectrum of the third region 228 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum. In some embodiments, the transmission spectrum of the fourth region 232 is or includes about the visible spectrum, about the near ultraviolet spectrum, and/or about the near infrared spectrum.

In some embodiments, the transmission spectrum of one or more of the first, second, third, or fourth regions (220,224,228,232) is, is substantially, includes, or includes the same transmission spectrum as one or more of any other of the first, second, third, or fourth regions (220,224,228,232). In some embodiments, the transmission spectrum of one or more of the first, second, third, or fourth regions (220,224,228,232) is different, substantially partially different, or partially different from the transmission spectrum of one or more of the other of the first, second, third, or fourth regions (220,224,228,232).

In some embodiments, the optical filter 158 (which may be a wavelength selective optical filter) includes: a first plurality of regions or spatially varying regions, which may be one or more of a first region, a second region, a third region, or a fourth region (220,224,228,232); and a second plurality of regions or spatially varying regions, which may be one or more of the first region, the second region, the third region, or the fourth region (220,224,228,232). The transmission spectrum of the first plurality of regions or regions of spatially varying regions may be different from the transmission spectrum of the second plurality of regions or regions of spatially varying regions.

Further, the optical sensor 154 may be active within a particular wavelength range. In other words, the optical sensor 154 may absorb and electronically register incident light, optimally absorb and electronically register incident light, or partially absorb and electronically register incident light in the visible, near ultraviolet, and/or near infrared spectra.

As depicted, one or more of the pixels 178 may be or serve as reference pixels 182. The reference pixel 182 may be used to reference one or more wavelengths to a lookup table of known thresholds or values. Such reference pixels 182 may be used to calibrate the optical system 150 and ensure that measurement conditions remain acceptable before, during, and/or after a measurement is performed.

In some embodiments, the optical system 150 includes an angle-selective filter 166. The angle-selective filter 166 limits the angle at which light is transmitted through the angle-selective filter 166 such that light rays greater than a particular angle of incidence, greater than an approximate angle of incidence, less than the particular angle of incidence, less than the approximate angle of incidence, greater than a first angle of incidence and less than a second angle of incidence, and greater than the approximate first angle of incidence and less than the second approximate angle of incidence are prevented, substantially prevented, or partially prevented from being transmitted through the angle-selective filter 166.

Furthermore, in some embodiments, the angle-selective filter 166 and/or the second angle-selective filter 167 may comprise a refractive structure or grating. The angle selective filter 166 may improve wavelength resolution during gradual transitions typical of absorption solutions.

In some embodiments, the optical system 150, the optical filter 158, and/or the angle-selective filter 166 define, produce, or include a spectrally sharp transition. The sharp transition in spectrum provides a more abrupt change in the percentage of light that is blocked or reflected to reduce or eliminate light reflection or transmission outside the desired wavelength range as compared to common reflective films having moderately sloped band edges that can cause reflection or transmission outside the desired wavelength range. In some embodiments, this sharp transition in the spectrum occurs at less than or less than about 75nm, 50nm, 40nm, 30nm, 20nm, or 10 nm. In some embodiments, the sharp transition in spectrum comprises or includes a change in transmittance of about 70%, 75%, 80%, 85%, 90%, 95%, or 99%. In some embodiments, the sharp spectral transition occurs at less than or less than about 75nm, 50nm, 40nm, 30nm, 20nm, or 10nm and includes or includes a transmission change of about 70%, 75%, 80%, 85%, 90%, 95%, or 99%.

In some embodiments, the optical filter 158 is birefringent, meaning that the refractive indices of light traveling along at least two of the three major and perpendicular directions (x-axis, y-axis, and z-axis) of the optical filter 158 are not equal. Furthermore, in certain implementations, the indices of refraction of light traveling along the three major and perpendicular directions (x-axis, y-axis, and z-axis) may not be equal.

In some embodiments, optical system 150 includes a polarizer, which may be any portion of first filter 190 and second filter 194 or different elements. Such polarizers may be circular polarizers, linear polarizers, reflective polarizers, or any other type of polarizer generally known to those skilled in the art. Polarizers allow light of certain polarizations to pass through while blocking other light. In some embodiments, optical system 150 includes a retarder. Retarders are used to change the polarization state of light passing therethrough. By the polarizing properties of the polarizers and the polarization changing properties of the retarders, and the small size of the pixels 178 relative to the

writing regions

198, 204 and the regions 220,224,228,232, the optical data sensed by the optical sensor 154 can be refined, thereby increasing the signal-to-noise ratio of the optical system and/or achieving a particular polarization to best suit the absorption properties of the optical sensor 154.

Further, the optical system may include a plurality of polarizers. In some embodiments, the light source may include a polarizer. In some embodiments, the optical system may include a second polarizer. In some embodiments, the light source includes a polarizer and the optical system 150 includes another polarizer. In some embodiments, the light source includes a polarizer and/or the optical system 150 includes a polarizer that is wavelength selective.

In some embodiments, the light source comprises a polarizer and/or the optical system 150 comprises a polarizer that is a linear polarizer. In some embodiments, the light source comprises a polarizer and/or the optical system 150 comprises a polarizer that is a circular polarizer. In some embodiments, the polarizers included with the light source and the polarizers included with the optical system 150 are linear polarizers, and each of the polarizers is arranged in parallel, or the polarization axes of the polarizers are arranged in parallel or substantially parallel. In some embodiments, the polarizers included with the light source and the polarizers included with the optical system 150 are linear polarizers, and each of the polarizers are arranged orthogonal to each other, or the polarization axes of the polarizers are arranged orthogonal to each other or substantially orthogonal to each other.

In some embodiments, the light source comprises polarizers and the optical system 150 comprises polarizers that are circular polarizers, and each of the polarizers are arranged in parallel, or the polarization axes of the polarizers are arranged in parallel or substantially parallel. In some embodiments, the polarizers included with the light source and the polarizers included with the optical system 150 are circular polarizers, and each of the polarizers are arranged orthogonal to each other, or the polarization axes of the polarizers are arranged orthogonal to each other or substantially orthogonal to each other.

In some embodiments, the light source 162 has, defines, and/or generates an emission spectrum of light. In some implementations, the emission spectrum of the light source 162 is wider than the transmission spectrum of one or more of the regions 220,224,228,232, writing

regions

198, 204,

non-writing regions

200, 206, and/or auxiliary writing regions 199. In some embodiments, the light source 162 includes one or more narrow emission peaks, which may be defined as 80nm full width at half maximum.

In some embodiments, the optical system 150 includes measurements taken via ambient light and/or light from the light source 162 described above that reaches the optical sensor 154 after passing through the optical filter 158. In some embodiments, multiple measurements may be taken at different times. In some embodiments, multiple measurements may be taken, with the optical sensor 154 being disposed at different angles of incidence, distances, and/or orientations with respect to one or more of the optical filter 158, the measurement object 170, and the reflector 163. In some embodiments, the optical filter 158 and/or the measurement object 170 may be measured at different angles of incidence, which may prove valuable because different angle measurements may yield varying data collected by the optical sensor 154 due to the disclosed angular relationship between the optical path, the optical filter 158, and the first and/or second angularly

selective filters

166, 167. In some embodiments, multiple measurements may be taken by the optical sensor 154 at different times, and in some embodiments, multiple measurements may be taken by the optical sensor 154 and a second optical sensor.

The measurement object may be animate or inanimate. In some embodiments, the measurement object 170 may be a human, animal, plant, living tissue, or other living object. In some embodiments, the measurement object may be a membrane, an electronic display, non-living plant or animal tissue, or any other inanimate object.

In some embodiments, the optical filter 158 may be curved, spherically curved, cylindrically curved, planar, flat, or have any other curved shape. Similarly, in some embodiments, the optical sensor 154 may be curved, spherically curved, cylindrically curved, planar, flat, or have any other curved shape. In some embodiments, the optical filter 158 and the optical sensor 154 may have the same or different types of curvatures.

Fig. 9A schematically illustrates an exemplary optical device 150. In some embodiments, the optical device 150 includes an optical sensor 154, an optical filter 158, and an angle-selective filter 166. The measurement object 170 and the light source 162 are also shown. In this embodiment, light emitted from the light source 162 passes through all elements of the optical device 150, reflects from the measurement object 170, then passes through the optical filter 158 and the angle-selective filter 166, and then reaches the optical sensor 154.

Fig. 9B illustrates another exemplary optical device 150 showing the optical sensor 154, the optical filter 158, the angle-selective filter 166, the light source 162, and the measurement object 170 in a different configuration than that shown in fig. 9A. In this embodiment, light from the light source 162 passes through the measurement object 170 en route to the remaining elements of the optical device 150.

Fig. 9C illustrates another exemplary optical device 150 showing the optical sensor 154, the optical filter 158, the angle-selective filter 166, the light source 162, and the measurement object 170 in a different configuration than that shown in fig. 9A and 9B. In this embodiment, the light source 162 is a transmissive light source, whereby at least a portion of the light emitted from the transmissive light source may be reflected from a portion of the measurement object 170, then pass through the transmissive light source and toward the remaining elements of the optical device 150.

Fig. 9D illustrates another exemplary optical device 150 showing the optical sensor 154, optical filter 158, angle-selective filter 166, light source 162, and measurement object 170 in a different configuration than that shown in fig. 9A, 9B, or 9C. This embodiment does not include a light source, and light from other sources (such as ambient light) reflects from the detectable object before passing through elements of the optical device 150 and reaching the optical sensor 154.

Fig. 9E illustrates another exemplary optical device 150 showing the optical sensor 154, optical filter 158, angle-selective filter 166, light source 162, and measurement object 170 in a different configuration than that shown in fig. 9A, 9B, 9C, or 9D. In this embodiment, the light source 162 is a polarized transmissive light source, whereby at least a portion of the light emitted from the polarized transmissive light source may be reflected from a portion of the measurement object 170, then pass through the polarized transmissive light source and through the cross polarizer 171, such that the optical sensor 154 detects only or substantially only the light reflected from the measurement object 170.

Fig. 9F shows another exemplary embodiment of an optical device 150. In this embodiment, light from the light source 162 passes through the measurement object 170 en route to the remaining elements of the optical device 150, including the second angularly selective filter 167, which will be described in more detail below.

Fig. 10 shows an exemplary cross-section of the optical filter 158. In some embodiments, optical filter 158 includes a down-converter 400 or down-conversion material. The downconverter 400 may absorb light at a first wavelength or within a first wavelength range and downconvert the light to a second wavelength or second wavelength range. The second wavelength may be longer than the first wavelength, and at least some wavelengths in the second wavelength range may be longer than at least some wavelengths in the first wavelength range. In some non-limiting examples, the first wavelength range may be 325nm-660nm, which may include the first wavelength, and the second wavelength range may be 380nm-760nm, which may include the second wavelength. Further, the downconverters 400,500 may absorb light of a relatively short wavelength, such as a first wavelength or first wavelength range, and emit light of a longer wavelength, such as a second wavelength or second wavelength range.

At least a portion of input light 412 entering the down-converter 400 via the input side 404 may be down-converted to a longer wavelength or wavelength range, becoming down-converted output light 420. The down-converted output light 420 may then exit the down-converter 400 via the output side 408 and/or the input side 404. Some input light 412 entering downconverter 400 via input side 404 may also pass downconverter 400 without being downconverted, thereby becoming output light 416 that may exit downconverter 400 via output side 408.

In some embodiments, as shown in fig. 11, downconverter 500 is similar to downconverter 400 shown in fig. 10. The downconverter 500 may absorb light at a first wavelength or within a first wavelength range and downconvert the light to a second wavelength or second wavelength range. The second wavelength may be longer than the first wavelength, and at least some wavelengths in the second wavelength range may be longer than at least some wavelengths in the first wavelength range. In some non-limiting examples, the first wavelength range may be 325nm-660nm, which may include the first wavelength, and the second wavelength range may be 380nm-760nm, which may include the second wavelength.

In some embodiments, downconverter 500 includes a low pass filter 530 in optical communication with input side 504 and a high pass filter 534 in optical communication with output side 508. Low pass filter 530 may be adjacent, near, or in contact with input side 504, and high pass filter 534 may be adjacent, near, or in contact with output side 508. Each of the low pass filter 530 and the high pass filter 534 may include a multilayer optical film. The low pass filter 530 may allow at least a portion of the first wavelength or first range of wavelengths to pass while reflecting at least a portion of the second wavelength or second range of wavelengths. The high pass filter 534 may allow at least a portion of the second wavelength or second range of wavelengths to pass while reflecting at least a portion of the first wavelength or first range of wavelengths.

In operation, at least a portion of input light 512 entering down-converter 500 via input side 500 and low pass filter 530 may be down-converted to a longer wavelength or wavelength range, becoming down-converted light 520. A portion of the down-converted light 520 may then exit the down-converter 500 as down-converted output light 522 via the output side 508 through the high pass filter 534. However, another portion of the down-converted light 520 may travel toward the low-pass filter 530, reflect from the low-pass filter 530, and then exit the down-converter 500 through the high-pass filter 534 via the output side 508. The low pass filter 530 may reflect all or only a portion of the down-converted light incident thereon.

Further, a portion of the input light 512 that is not down-converted may be reflected from the high pass filter 534 as reflected input light 538, and may then be down-converted to down-converted reflected input light 542 in the down-converter 500. This down-converted reflected input light 542 may then be reflected from the low pass filter 530 before exiting the down-converter 500 via the output side 508 and passing through the high pass filter 534. Downconverters 400,500 may include fluorescent, phosphorescent materials and chemicals, and may include dyes, pigments or quantum dots.

It should be understood that, as illustrated in fig. 10 and 11, the downconverters 400,500 may be included in one or more of the optical filter 158, the first filter 190, the second filter 194, an adhesive (e.g., for joining the first filter 190 and the second filter 194 or for use elsewhere in the optical filter 158, the remote optical device 160, or the optical system 150), the writing region 198, the auxiliary writing region 199, the non-writing region 200, the first region 220, the second region 224, the third region 228, and/or the fourth region 232. Additionally, portions of the optical filter 158 other than the portion of the optical filter 158 that includes the downconverters 400,500 may be free of the

downconverters

400, 500.

In various embodiments, the

input side

404, 504 or the low pass filter 530 may define the front surface 209 of the optical filter 158. In various embodiments, the output sides 408, 508 or the high-pass filter 534 may define a back surface of the optical filter 158, which may be substantially opposite the front surface 209.

The optical filter 158 may also include a reference region 457. The reference area 457 may form all or a portion of the first filter 190, the second filter 194, or one or more of the writing region 198, the auxiliary writing region 199, the non-writing region 200, the first region 220, the second region 224, the third region 228, and the fourth region 232. The reference region 457, which may include the down-converters 400,500, may be calibrated to a known transmission band, down-conversion performance, or other optical characteristic to enable a comparison between any portion of the optical filter 158 outside of the reference region 457 and the reference region 457, and to calibrate the optical filter 158 or other measured parameter.

In some embodiments, as best shown in fig. 12, the optical filter 158 may include a plurality of discrete elements. For example, the optical filter 158 may include a plurality of first regions 220 and a plurality of second regions 224 arranged in a spatially varying pattern, an example of which is shown in fig. 12. It should be understood that any arrangement and/or arrangement of the spatially varying write zones 198, auxiliary write zones 199, first regions 220, second regions 224, third regions 228, and fourth regions 232 as a plurality of discrete elements is within the scope of the present disclosure.

In some embodiments, as best shown in fig. 13, the optical filter 158 may include a plurality of orifices, holes, or open regions 477. The vents 477 may form a spatially varying pattern. The portion of optical filter 158 not defined by aperture 477 may include first filter 190 and/or second filter 194. Further, the orifice 477 may form the first, second, third, and/or fourth regions 220,224,228, and 232, while other of the first, second, third, and fourth regions 220,224,228, and 232 may be formed by portions of the optical filter 158 outside of the orifice 477. Additionally, as illustrated in fig. 10 and 11, downconverters 400,500 may be included in the portion of optical filter 158 outside of aperture 477.

All cited references, patents, and patent applications cited above are hereby incorporated by reference in their entirety in a consistent manner. In the event of inconsistencies or contradictions between the incorporated reference parts and the present application, the information in the preceding description shall prevail. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Accordingly, the disclosure is intended to be limited only by the claims and the equivalents thereof.

Claims

1. An optical system, the optical system comprising:

an optical sensor;

a plurality of light-sensitive pixels disposed on the optical sensor;

a wavelength-selective optical filter in optical communication with the plurality of light-sensitive pixels, the wavelength-selective optical filter disposed remotely from the optical sensor; and

a plurality of spatially varying regions disposed in the optical filter, at least one region of the plurality of spatially varying regions comprising a down-converter.

2. The optical system of claim 1, further comprising a high pass filter disposed at an output side of the down-converter.

3. The optical system of claim 1, further comprising a low pass filter disposed at an input side of the down converter.

4. The optical system of claim 1, further comprising a reflector, the wavelength-selective optical filter and measurement object each being disposed along an optical path between the reflector and the optical sensor.

5. The optical system of claim 1, further comprising a light source and a reflector, wherein the wavelength-selective optical filter and measurement object are each disposed along an optical path between the light source and the reflector.

6. The optical system of claim 1, further comprising a light source, wherein the wavelength-selective optical filter and measurement object are each disposed along an optical path between the light source and the optical sensor.

7. The optical system of claim 1, wherein the wavelength-selective optical filter is disposed along an optical path between the optical sensor and a measurement object.

8. The optical system of claim 1, wherein a measurement object is disposed along an optical path between the wavelength selective optical filter and the optical sensor.

9. An optical device, the optical device comprising:

an optical sensor;

a plurality of light-sensitive pixels disposed on the optical sensor;

a wavelength-selective optical filter in optical communication with the plurality of light-sensitive pixels;

a first plurality of spatially varying regions disposed in the optical filter, at least one region of the first plurality of spatially varying regions comprising a down-converter; and

a second plurality of spatially varying regions disposed in the optical filter.

10. The optical device of claim 9, further comprising a high pass filter disposed at an output side of the down-converter.

11. The optical device of claim 9, further comprising a low pass filter disposed at an input side of the down converter.

12. The optical device of claim 9, wherein the wavelength-selective optical filter comprises a reference region.

13. The optical arrangement of claim 9, wherein the wavelength selective optical filter is flexible.

14. The optical apparatus of claim 9, wherein at least one of the first plurality of spatially varying regions is a different size than at least one of the second plurality of spatially varying regions.

15. An optical device, the optical device comprising:

a wavelength selective optical filter, the filter comprising:

a second plurality of spatially varying regions disposed in the optical filter.